Scatter3d plot

The scatter3d plot creates a three-dimensional scatter plot of the data.

import plopp as pp
import scipp as sc
import numpy as np

Scatter plot using a positions vector

The easiest way to generate a scatter plot is to use a coordinate of the data array that contains data of the vector3 dtype.

We first generate some fake data, meant to represent clusters of points in a three-dimensional space.

nclusters = 100
npercluster = 1000

position = np.zeros((nclusters, npercluster, 3))
values = np.zeros((nclusters, npercluster))

for n in range(nclusters):
    center = 500.0 * (np.random.random(3) - 0.5)
    r = 20.0 * np.random.normal(size=[npercluster, 3])
    position[n, :] = r + center
    values[n, :] = np.linalg.norm(r, axis=1) + n

da = sc.DataArray(
    data=sc.array(dims=['row'], values=values.flatten(), unit='K'),
    coords={
        'position': sc.vectors(
            dims=['row'], unit='m', values=position.reshape(nclusters * npercluster, 3)
        )
    },
)
da

scipp.DataArray (3.05 MB)

• Dimensions:
  • row: 100000
• Coordinates: (1)
  • position
    (row)
    vector3
    m
    [-254.19850501 17.25011046 111.4732856 ], [-244.64067686 -34.31500281 105.17499688], ..., [ 157.9463904 -152.17151925 -167.69917058], [ 148.22231008 -197.84766741 -202.43787627]

    Values:
    array([[-254.19850501,   17.25011046,  111.4732856 ],
           [-244.64067686,  -34.31500281,  105.17499688],
           [-263.3632532 ,   -1.58272215,  102.55887797],
           ...,
           [ 125.14408696, -169.87649834, -171.68486952],
           [ 157.9463904 , -152.17151925, -167.69917058],
           [ 148.22231008, -197.84766741, -202.43787627]], shape=(100000, 3))

• Data: (1)
  • (row)
    float64
    K
    34.316, 41.650, ..., 129.624, 135.338

    Values:
    array([ 34.31607479,  41.6503339 ,  40.49132137, ..., 126.47354015,
           129.62406314, 135.33842588], shape=(100000,))

We then simply specify the name of the coordinate that contains the vector positions using the pos argument:

pp.scatter3d(da, pos='position', color='black', size=2)

Scatter plot with colorbar

To make a scatter plot with a colorbar mapping data values to colors, use cbar=True.

pp.scatter3d(da, pos='position', cbar=True, size=2)

Scatter plot using individual coordinates

It is also possible to create scatter plots using three individual coordinate names for the x, y, z dimensions:

time = np.linspace(0, 10, 50)
x = np.cos(time)
y = np.sin(time)

da = sc.DataArray(
    data=sc.array(dims=['row'], values=time),
    coords={
        'x': sc.array(dims=['row'], unit='m', values=x),
        'y': sc.array(dims=['row'], unit='m', values=y),
        'time': sc.array(dims=['row'], unit='s', values=time),
    },
)

pp.scatter3d(da, x='x', y='y', z='time', size=0.2, cbar=True)